Category Archive: Case Studies
Improperly Used Space Heaters Can Be Dangerous
As the temperature outside slides from the cold to the “bitter” cold range on the thermometer, most people tend to turn the heat on inside their home. Some homes, however, do not have whole house heat or sufficient heating capacity and therefore the occupants may rely on portable space heaters. Portable space heaters, used properly, can be a good choice to warm a small area of a home. Unfortunately, while they can warm your cold and tingling hands and feet, they can also warm nearby materials to the point of ignition. Read More
If There is a Human, There are Human Factors
If there is a human involved in the case, there is a good chance that human factors theories and principles will be applicable. Human factors is the study of people interacting with their surrounding environment. A human factors expert applies their knowledge of human capabilities and limitations to each unique case to assess the physical, sensory, and cognitive factors that caused a person to behave a certain way within the surrounding environment.
Consider the following situations in which a human factors expert would be beneficial: Read More
Scared of Water, or Prefer to Get Drenched? Fire Suppression with Preaction and Deluge Systems
In the two previous blogs, we first discussed wet sprinkler systems (Wet), the most basic and most common fire system type followed by dry sprinkler systems (Dry), which are a bit more complicated. Ratcheting up another level, in this last edition on sprinkler systems, let’s take a look together at preaction and deluge systems. These can be complex and variable, so we’ll operate at the 30,000 ft level. Read More
When a DRY Fire Sprinkler System Leaves You Soaked
In the previous blog , I discussed the most basic and most common fire system type: wet sprinkler systems. The possible failure areas discussed with wet systems will also apply to dry sprinkler systems (control valves closed, obstructions, issues in the system, installation, or deficiencies with inspection, testing, and maintenance). Dry systems are even more prone to obstructions than wet systems, so close attention should be paid to that possibility. Read More
The Collision Reconstruction Matrix
It’s mid-January, the high today is 28 degrees with lows in the teens as the Carolinas are in the grip of a Canadian cold front and I’m on call tonight. The phone rings at 3:00 am; yes Sir, three cars with two fatalities, I-85 northbound, yes Sir, on the way. Despite the hurdles that lie in front of me – cold, fatigue, the loss of life – my job with the South Carolina Highway Patrol Multi-Disciplinary Accident Investigation Team (MAIT) is to investigate, document, and ultimately prosecute chargeable collisions. To properly reconstruct this collision, three essential and distinct categories must be investigated and documented in order to provide a well-founded explanation of the series of events prior to, during, and after the collision regarding the human, the vehicle, and the environment; this investigative technique is known as the 9-cell collision reconstruction matrix. Read More
The Use of Taglines to Control Crane Loads
The adequacy of a crane’s load line to support the weight of the object being lifted is an obvious concern when evaluating a crane lifting operation. Less obvious, but often equally important, is the presence and adequacy of taglines to provide control of the load orientation.
Taglines are simply ropes or lines that are Read More
Conveyor Backstops: Sometimes One Isn’t Enough, Part 2
This is the second in a two-part blog series about conveying equipment that severely injured a worker at a mine. In case you missed it, click here to read Part 1 where I describe the incident and the mining equipment. In this part, I will discuss my engineering analysis of the incident and the machinery involved and share the conclusions I reached.
The injured miner was a front-end loader operator. He was not a maintenance worker. He simply responded to a radio request for help with the conveyor. Power to the electric conveyor motors was locked out, but none of the maintenance workers did anything to lock out or block the hazardous gravitational potential energy in the heavy load of stone on the belt. Read More
Conveyor Backstops: Sometimes One Isn’t Enough, Part 1
This is the first of a two-part blog series describing an incident involving conveying machinery that seriously injured a miner. Part 1 describes the machinery and the incident. In Part 2 I will summarize my engineering analysis of the incident and share the conclusions I reached.
A loaded, inclined conveyor belt may contain hazardous levels of energy due to gravity. To protect workers, anti-reverse devices called backstops are installed on inclined conveyors to prevent unexpected downhill movement. The Conveyor Equipment Manufacturer’s Association (CEMA) defines a backstop as: Read More
Lack of HVAC System Design and Poor Installation Lead to Extreme Conditions
Construction defects can appear in many forms. The building does not necessarily have to fall down. There are many types of construction defects, including roof leaks, water intrusion into walls, as well as Heating, Ventilation, and Air Conditioning (HVAC) defects.
One extreme example of this was an office complex I was called to for an investigation of the source of mold observed on the walls. The occupants complained that they could not find a temperature setting on the thermostat where they could make the office comfortable. When I inspected the office, I couldn’t believe what I was seeing. A band of black mold Read More
